The cause of pancreatitis in cats is usually unknown. It is often associated with neutrophilic cholangitis and/or IBD (so-called triaditis). The role of diet in the aetiology of pancreatitis in cats is unclear; there is no evidence that feeding a high fat diet precipitates pancreatitis in cats; however, this may still be important in some cats.
Clinical signs are often very vague, frequently not being more than lethargy/malaise and inappetence. Vomiting, nausea and more obvious abdominal pain may or may not be present. Diarrhoea may also be a feature.
Diagnosis of pancreatitis can be challenging, in view of the non-specific clinical signs, the frequent presence of concurrent disease and the limitations in diagnostic testing. Most laboratory findings are reflective of underlying or concurrent disease. There is often mild hyperbilirubinaemia with normal liver enzyme levels (but may be increased if concurrent cholangitis), and hypocalcaemia may be present.
Ultrasonography may show pancreatic enlargement and hypoechoic areas and there may be hyperechoic fat surrounding the pancreas, but a lack of ultrasonographic abnormalities is common, and abnormalities can be subtle and require ultrasound expertise to identify.
Amylase and lipase assays are not useful in cats. Feline trypsin-like immunoreactivity (fTLI) may be elevated, but is often normal. Feline pancreatic lipase immunoreactivity (fPLI) is the most sensitive and specific laboratory test available for the diagnosis of feline pancreatitis, particularly in cats with moderate-severe disease. However a normal fPLI does not completely exclude pancreatitis, particularly chronic low grade disease. An in-house SNAP fPLI test is also available (IDEXX); however, this does not provide a quantitative result, but gives a positive or negative result. It is sensitive test; however, is less specific and therefore false positive results may be more frequently obtained. A positive SNAP test result should be followed up with a quantitative fPLI assay.
Serum cobalamin (Vitamin B12) is often low in cases of pancreatitis and so should ideally be measured and supplemented as necessary.
Despite the many advances in veterinary medicine, there is still a huge amount that we do not know when it comes to optimally treating pancreatitis, particularly in cats.
There is no evidence for specific treatment, and we are largely limited to managing the disease symptomatically. We also need to consider concurrent diseases, since frequently cats have a combination of inflammatory liver, pancreatic and intestinal disease and this may also influence management. Furthermore, other concurrent diseases such as diabetes mellitus or hepatic lipidosis can also be present.
Management of pancreatitis is largely based on supportive therapy and dietary measures in addition to management of complications and/or concurrent diseases. We have little knowledge of how to treat the pancreatitis itself, and even in human medicine, the only treatments proven to be beneficial are fluid therapy, pain management and nutritional management. Reviewing recent drug history and evaluating for concurrent and underlying diseases may also influence treatment.
Treatment priorities will vary depending on severity of clinical signs and whether pancreatitis is acute or chronic, however, generally consists of:
Intravenous fluid therapy and electrolyte supplementation.
Crystalloids (lactated Ringers or 0.9% NaCl) are usually recommended for initial replacement. The aggressiveness of fluid therapy is dependent on presenting signs and severity of the pancreatitis, whether it is acute or chronic. Attention must also be paid to electrolyte abnormalities, in particular hypocalcaemia and hypokalaemia.
Although intractable vomiting is not common in feline patients, many cats will benefit from administration of anti-emetics, since nausea is an important cause of inappetance and development of food aversion. Maropitant administered subcutaneously or orally appears to be an effective anti-emetic in cats and is usually the author's first choice now. It may also have visceral analgesic properties. Metoclopramide administered in fluids as a constant rate infusion at 1–2 mg/kg/24 hours can also be effective. This has the benefit of pro-kinetic activity also, and so may be more useful in cats that have ileus associated with their pancreatitis.
Clinicians should be aware that abdominal pain is often not appreciable in these patients, but is certainly likely to be present, and the response in demeanour and appetite to analgesia can often be dramatic so should never be withheld. Opioid analgesia is therefore recommended in any cats with confirmed or suspected pancreatitis. Buprenorphine (0.01–0.02 mg/kg IM, IV, SC or sublingually every 8 hours) is usually effective. Where more potent analgesia is required, methadone, morphine, or fentanyl can be useful. Non-steroidal anti-inflammatory drugs should generally be avoided due to increased risks of renal toxicity in dehydrated or hypovolaemic patients, and GI effects in vomiting patients.
The priority with nutritional therapy depends partly on the clinical presentation, whether pancreatitis is acute or chronic and presence of concurrent diseases. In dogs with pancreatitis, complete pancreatic rest and nil per os are recommended if the patient is vomiting frequently. In cats, vomiting is less common which allows enteral nutrition to be addressed early in the course of treatment. Hepatic lipidosis is common in cats with pancreatitis and is associated with a poorer prognosis. Appropriate nutrition can be essential to prevent hepatic lipidosis developing or worsening. In cases of acute pancreatitis that are persistently anorexic, a feeding tube may be required, once any vomiting has been adequately controlled. In milder cases, appetite stimulants such as mirtazapine or cyproheptadine may be sufficient. Care should be taken to ensure adequate anti-emetic therapy and analgesia is being used before starting appetite stimulants, as occasionally the result of stimulating appetite whilst the cat may develop pain and/or nausea upon eating, can contribute to food aversion. Having said all this, there may also be cases where a short period of starvation (e.g., 24–36 hours) is actually beneficial.
The type of diet that is most appropriate to use is really unknown. In contrast to dogs, where feeding a low fat diet is important, this has not been shown in cats, and frequently any diet that the cat will eat, or a critical care diet if being tube fed, are used. However, it is becoming more commonly thought that dietary fat is important in feline pancreatitis, at least in some cases, and the author has come across cases where high fat diets appear to noticeably worsen signs of pancreatitis. A low fat, low residue easily digestible diet is probably most appropriate to use. However, in cases of IBD, a novel protein diet may be more appropriate, and this creates conflict in cases with concurrent IBD and pancreatitis, where the ideal diet may be a low fat novel protein diet, but such a commercial diet is not available. Very often, trial and error with different diets is required to find the most suitable one for an individual cat, but every attempt should be made to feed a relatively low fat diet.
Pancreatitis has usually been thought to be sterile in cats, with little indication for antibiotics, apart from where there is concurrent cholangitis, or with severe pancreatitis where there may be increased risk of bacterial translocation from the intestine. However, there is some emerging evidence, using more sensitive techniques to detect bacteria, that some cats with chronic pancreatitis have gram-negative bacteria associated with the wall in and around the pancreatic ducts and persisting resident bacteria may contribute to chronic inflammatory changes. Therefore, there may be a requirement for antibiotic treatment in some cases.
Antacids are not routinely advised in patients with pancreatitis unless there is evidence of gastric ulceration. Omeprazole is a more potent antacid than H2 blockers. If ileus is present, then ranitidine can be useful both as an antacid but also due to its prokinetic effects, and minimal effects on the hepatic P450 enzyme system compared to other H2 blockers.
Oral Pancreatic Enzyme Extracts
Pancreatic enzyme supplementation has been reported to reduce pain in humans with chronic pancreatitis but this is controversial. There is no evidence that they are beneficial in cats. However, the author has used pancreatic enzymes in some cats, particularly ones that appear to have pain associated with eating, and that appear to have fat maldigestion. It is difficult to evaluate if they have been beneficial. Some cats with chronic pancreatitis will develop exocrine pancreatic insufficiency and then they will be required.
B12 deficiency is common in these patients, especially when concurrent GI disease is present, and therefore supplementation is often indicated, either empirically, or following demonstration of low serum B12.
Corticosteroids are generally not indicated unless they are required for concurrent IBD. However, in some cases they may have a role in the prevention of ongoing inflammation and fibrosis in cases of chronic recurring pancreatitis. There is, however, also concern that they may be contraindicated in pancreatitis, particularly acute disease. Therefore, when used they should be used with caution and close clinical monitoring, alongside considering monitoring fPLI concentrations.